Evidence must be

and
for it to be considered effective in supporting a claim.

credible and relevant

To be considered effective in supporting a claim, evidence must be relevant and credible.

1. Relevance: The evidence should directly address the claim being made. It should provide information that directly supports or refutes the claim, and not be tangential or unrelated.

2. Credibility: The evidence should come from reliable and trustworthy sources. It should be backed by proper research, expertise, and evidence-based reasoning. The credibility of the source can be assessed by considering factors such as the author's qualifications, the source's reputation, and whether the information has been peer-reviewed or published in reputable journals.

So, in summary, evidence must be relevant to the claim being made and come from credible sources to be considered effective in supporting that claim.